At present, there are two common schemes in the handwriting input field of mobile terminals: input via a resistive touch screen and input via a capacitive touch screen.
An input principle of the resistive touch screen is: when a corresponding stylus is adopted for writing on such touch screen, a part where the stylus touches the touch screen may deform due to the change of a touch pressure between the stylus and the touch screen, so that the resistance of this point is changed to implement touch input of the resistive touch screen. The resistive touch screen is characterized in that it has no particular requirement on the stylus and a relatively low cost but it cannot support identification of multi-point touch. At present, the resistive touch screen is applied to a large number of middle-end and low-end mobile phones with touch screens.
An input principle of the capacitive touch screen is: a capacitive sensing device is built in the screen to form an inductance with a charged object which gets close enough to the capacitive sensing device, and the capacitive sensing device absorbs partial inductive charge through the inductance, and determines a specific touch operation location by detecting the row and column where the absorbed inductive charge is located. The capacitive touch screen can support the multi-point touch but has a certain requirement on an input medium. Generally, only a charged object can implement input. For example, the input medium is generally a finger of a person. But now, some techniques for handwriting input on the capacitive touch screen using a special stylus also appear.
Along with the emergence of high-end mobile terminal products such as tablet Personal Computers (PCs) and smart phones, the mobile terminal is increasingly becoming an important tool for daily record and writing of people. Therefore, people propose an increasingly strict requirement on each function of the mobile terminal. For example, for such product as a tablet PC or a smart phone with a large screen, people hope to utilize its accessary stylus to implement more functions besides existing text control and writing functions of the stylus, for example utilizing the stylus to implement a function like paper writing on the screens of these mobile terminals, such as drawing, signature and stamping. However, there is still no such technology in the related art.